全文获取类型
收费全文 | 343篇 |
免费 | 8篇 |
国内免费 | 17篇 |
专业分类
测绘学 | 171篇 |
大气科学 | 7篇 |
地球物理 | 8篇 |
地质学 | 34篇 |
海洋学 | 9篇 |
综合类 | 53篇 |
自然地理 | 86篇 |
出版年
2023年 | 3篇 |
2022年 | 7篇 |
2021年 | 4篇 |
2020年 | 8篇 |
2019年 | 7篇 |
2018年 | 8篇 |
2017年 | 16篇 |
2016年 | 17篇 |
2015年 | 15篇 |
2014年 | 20篇 |
2013年 | 45篇 |
2012年 | 26篇 |
2011年 | 24篇 |
2010年 | 18篇 |
2009年 | 20篇 |
2008年 | 25篇 |
2007年 | 18篇 |
2006年 | 20篇 |
2005年 | 17篇 |
2004年 | 18篇 |
2003年 | 11篇 |
2002年 | 5篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
排序方式: 共有368条查询结果,搜索用时 828 毫秒
81.
82.
This paper explores the phenomenon of local climate perception and the extent to which public perceptions match climate conditions as recorded in instrumental climate data. We further examine whether perceptions of changes in local climates are influenced by prior beliefs about global warming, through the process of motivated reasoning. Using national survey data collected in the United States in 2011, we find that subjective experiences of seasonal average temperature and precipitation during the previous winter and summer were related to recorded conditions during each season. Beliefs about global warming also had significant effects on subjective experiences with above-normal temperatures, particularly among those who believed that global warming is not happening. When asked about the summer of 2010, those who believed that global warming is not happening were significantly less likely to report that they had experienced a warmer-than-normal summer, even when controlling for demographics and local climate conditions. These results suggest that the subjective experience of local climate change is dependent not only on external climate conditions, but also on individual beliefs, with perceptions apparently biased by prior beliefs about global warming. 相似文献
83.
《地学前缘(英文版)》2023,14(2):101521
Lithofacies paleogeography is a data-intensive discipline that involves the interpretation and compilation of sedimentary facies. Traditional sedimentary facies analysis is a labor-intensive task with the added complexity of using unstructured knowledge and unstandardized terminology. Therefore, it is very difficult for beginners or non-geology scholars who lack a systematic knowledge and experience in sedimentary facies analysis. These hurdles could be partly alleviated by having a standardized, structured, and systematic knowledge base coupled with an efficient automatic machine-assisted sedimentary facies identification system. To this end, this study constructed a knowledge system for fluvial facies and carried out knowledge representation. Components include a domain knowledge graph for types of fluvial facies (meandering, braided and other fluvial depositional environments) and their characteristic features (bedforms, grain size distribution, etc.) with visualization, a method for query and retrieval on a graph database platform, a hierarchical knowledge tree-structure, a data-mining clustering algorithm for machine-analysis of publication texts, and an algorithm model for this area of sedimentary facies reasoning. The underlying sedimentary facies identification and knowledge reasoning system is based on expert experience and synthesis of publications. For testing, 17 sets literature publications data that included details of sedimentary facies data (bedforms, grain sizes, etc.) were submitted to the artificial intelligence model, then compared and validated. This testing set of automated reasoning results yielded an interpretation accuracy of about 90% relative to the published interpretations in those papers. Therefore, the model and algorithm provide an efficient and automated reasoning technology, which provides a new approach and route for the rapid and intelligent identification of other types of sedimentary facies from literature data or direct use in the field. 相似文献
84.
85.
Roderic?Beraclaramunt@ecole-navale.fr" title="bera claramunt@ecole-navale.fr" itemprop="email" data-track="click" data-track-action="Email author" data-track-label="">Email author Christophe?Claramunt 《Journal of Geographical Systems》2003,5(4):353-379
This paper introduces several topology-based measures that characterise proximity relationships between regions in a spatial system. These measures are derived from a relative adjacency operator that is computed from the dual graph of a spatial system. The operator is flexible as the respective importance of neighbouring and outlying regions can be parameterised. Given a reference region in a spatial system, we also show how the relative adjacency supports the analysis of the relative distribution of other regions, and how these regions are clustered with respect to that reference region. Extensions of the relative adjacency integrate additional spatial and thematic criteria. The properties of the relative adjacency are illustrated by means of reference examples and a case study.The authors thank the referees for their constructive comments and suggestions that significantly improved the quality of the paper. 相似文献
86.
选择专题地图表示方法的推理研究 总被引:3,自引:0,他引:3
分析了地图制图知识的表达与应用方法,研究了专题地图制图知识中应该考虑的因素,提出了一种选择专题地图表示的推理方法. 相似文献
87.
贝叶斯网络结构学习及其应用研究 总被引:5,自引:0,他引:5
阐述了贝叶斯网络结构学习的内容与方法 ,提出一种基于条件独立性 (CI)测试的启发式算法。从完全潜在图出发 ,融入专家知识和先验常识 ,有效地减少网络结构的搜索空间 ,通过变量之间的CI测试 ,将全连接无向图修剪成最优的潜在图 ,近似于有向无环图的无向版。通过汽车故障诊断实例 ,验证了该算法的可行性与有效性。 相似文献
88.
线与面的空间拓扑关系组合推理 总被引:6,自引:0,他引:6
在原先所提出的空间拓扑关系组合描述的基础上,进一步完善了利用基本空间拓扑关系进行组合推理的方法,并建立了推理表,详细绘制了线与面的所有空间拓扑关系图。 相似文献
89.
In Korea most of the old mine workings were worked with room and pillar method or sublevel caving method and today they possess
great possibility of surface subsidence especially for shallow depth mines. In most of the cases, mine roadways, rooms and
pillars are irregular in shape and information about the local geology is uncertain. For these reasons, it is difficult to
standardize the estimating method of subsidence especially sinkhole type over abandoned mine area. This paper describes the
application procedure for the fuzzy reasoning techniques to analyze the possibility of sinkhole occurrences over abandoned
mines. This technique is implemented in software which can simplify the analysis procedure and present the possibility of
sinkhole subsidence without having precise information about local geological/mining conditions. This technique has been applied
to forecast sinkhole possibilities at Bonghwa site where a massive sinkhole has already been occurred. 相似文献
90.
LBS中位置及其语义的研究 总被引:4,自引:0,他引:4
阐述了两种LBS位置表示方法,引入了语义位置的概念,对现有的语义位置概念作了修正。强调了位置属性也是语义位置的重要组成部分。通过对位置概念内涵和外延的分析,讨论了位置属性所包括的内容;运用层次建模,实现了位置之间关系的描述。为了能够规范化地描述语义位置,运用本体技术,对位置所包含的语义信息进行了描述,建立了能够被计算机识别和处理的OWI。位置本体模型。通过对语义位置的本体建模,实现了位置信息的知识化描述,为实现个性化服务奠定了基础。 相似文献